98 V70 brake noise

[Edwin S.]

I replaced pads and turned rotors on the front. Ever since then, after
applying the brakes about 7 times, a horrendous squeal starts and doesn't
go away until the brakes cool down. My mechanic has no idea why. When
brakes are cold,no noise at all. BTW, these are ceramic pads. My
mechanic's wife's car is a 97 850 and it does the same thing.

 

[Michael Pardee]

I replaced pads and turned rotors on the front. Ever since then, after
applying the brakes about 7 times, a horrendous squeal starts and doesn't
go away until the brakes cool down. My mechanic has no idea why. When
brakes are cold,no noise at all. BTW, these are ceramic pads. My
mechanic's wife's car is a 97 850 and it does the same thing.

A good bleeding might help (or it might not.) I'm thinking if a trace of
moisture has invaded the fluid - as it always does over time - when hot it
would produce vapor pressure and make the fluid slightly compressible. The
new pads might not tolerate that as well as the old ones did, for whatever
reason.

This fix falls under the "cheap enough, couldn't hurt, might help" category.

Mike

 

[..................................................]

I replaced pads and turned rotors on the front. Ever since then, after
applying the brakes about 7 times, a horrendous squeal starts and doesn't
go away until the brakes cool down. My mechanic has no idea why. When
brakes are cold,no noise at all. BTW, these are ceramic pads. My
mechanic's wife's car is a 97 850 and it does the same thing.

You know...there is a whole science regarding brake squeal.
Volvo instructs that the rotors on your car never be turned...and there
is solid science behind that. When they're done with, they are DONE.
Often, the squeal is amplified by the backing-plate which acts as a
radio speaker. Often if you remove the inner brake shield and leave
everything else alone, the squeal will go away permanently. The VAST
majority of brake shops don't really know how to turn a rotor, much less
a drum. The guys that REALLY know how to do it are making about 60k a
year...and they're not working in brake shops.
Cut your losses, replace the rotors and pads...or upgrade them to
something really trick. Once rotors are turned by someone who really
doesn't know the science, the rotors are lunched.

 

[..................................................]

A good bleeding might help (or it might not.) I'm thinking if a trace of
moisture has invaded the fluid - as it always does over time - when hot it
would produce vapor pressure and make the fluid slightly compressible. The
new pads might not tolerate that as well as the old ones did, for whatever
reason.

This fix falls under the "cheap enough, couldn't hurt, might help" category.

Mike

Squealing has nothing to do with the fluid. If it did, the brakes would
have been squealing before hand.

 

[zencraps]

Remove the pads and put some (orange colored liquid) Disc Brake Quiet
on the rear of the pads and on the pins.